I haven't left the city yet. However I do have a pitch fork and axe just in case.
I have thought about the end of days on more than one occasion but then I start to worry about the gene pool and what would happen when I die and my children are left on their own. I don't want to some sort of sequel to Flowers in the Attic so a sizable community is a must. Ignoring the need for defence, I have always thought that a population of 30 000 like minded individuals would be easily supported by a city the size of Brisbane has today, with all it's current resources.
Of course some amenities would be difficult to maintain. Working sewage and rationed energy supplies are handy but I'd imagine we could still sustain ourselves. Who knows, perhaps from adversity our knowledge of science may get a different kick along and solar energy would able to power our society. Bikes instead of private cars, handy man instead of a cop. The internet would be gone but libraries still exist. I just have to decide whether The Daring book for Girls or the SAS handbook would become our Bible. Perhaps an Old and New Testament.